All-small-molecule organic solar cells with over 14% efficiency by optimizing hierarchical morphologies

AbstractThe high efficiency all-small-molecule organic solar cells (OSCs) normally require optimized morphology in their bulk heterojunction active layers. Herein, a small-molecule donor is designed and synthesized, and single-crystal structural analyses reveal its explicit molecular planarity and compact intermolecular packing. A promising narrow bandgap small-molecule with absorption edge of more than 930 nm along with our home-designed small molecule is selected as electron acceptors. To the best of our knowledge, the binary all-small-molecule OSCs achieve the highest efficiency of 14.34% by optimizing their hierarchical morphologies, in which the donor or acceptor rich domains with size up to ca. 70 nm, and the donor crystals of tens of nanometers, together with the donor-acceptor blending, are proved coexisting in the hierarchical large domain. All-small-molecule photovoltaic system shows its promising for high performance OSCs, and our study is likely to lead to insights in relations between bulk heterojunction structure and photovoltaic performance.

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With PBDB-T as the Donor, the PCE of Non-Fullerene Organic Solar Cells Based on Small Molecule INTIC Increased by 52.4%

Materials ◽

10.3390/ma13061324 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1324 ◽

Cited By ~ 1

Author(s):

Weifang Zhang ◽

Zicha Li ◽

Suling Zhao ◽

Zheng Xu ◽

Bo Qiao ◽

...

Keyword(s):

Solar Cells ◽

Small Molecule ◽

Organic Solar Cells ◽

High Performance ◽

Short Circuit ◽

Photovoltaic Performance ◽

Short Circuit Current ◽

Production Costs ◽

Higher Carrier Mobility ◽

Carrier Transportation

At present, most high-performance non-fullerene materials are centered on fused rings. With the increase in the number of fused rings, production costs and production difficulties increase. Compared with other non-fullerenes, small molecule INTIC has the advantages of easy synthesis and strong and wide infrared absorption. According to our previous report, the maximum power conversion efficiency (PCE) of an organic solar cell using PTB7-Th:INTIC as the active layer was 7.27%. In this work, other polymers, PTB7, PBDB-T and PBDB-T-2F, as the donor materials, with INTIC as the acceptor, are selected to fabricate cells with the same structure to optimize their photovoltaic performance. The experimental results show that the optimal PCE of PBDB-T:INTIC based organic solar cells is 11.08%, which, thanks to the open voltage (VOC) increases from 0.80 V to 0.84 V, the short circuit current (JSC) increases from 15.32 mA/cm2 to 19.42 mA/cm2 and the fill factor (FF) increases from 60.08% to 67.89%, then a 52.4% improvement in PCE is the result, compared with the devices based on PTB7-Th:INTIC. This is because the PBDB-T:INTIC system has better carrier dissociation and extraction, carrier transportation and higher carrier mobility.

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Asymmetrical squaraines for high-performance small-molecule organic solar cells with a short circuit current of over 12 mA cm−2

Chemical Communications ◽

10.1039/c5cc00704f ◽

2015 ◽

Vol 51 (28) ◽

pp. 6133-6136 ◽

Cited By ~ 30

Author(s):

Yao Chen ◽

Youqin Zhu ◽

Daobin Yang ◽

Qian Luo ◽

Lin Yang ◽

...

Keyword(s):

Solar Cells ◽

Small Molecule ◽

Organic Solar Cells ◽

High Performance ◽

Short Circuit ◽

Photovoltaic Performance ◽

Short Circuit Current ◽

Squaric Acid ◽

Squaraine Dyes

Asymmetrical squaraine dyes with two aryl groups directly linked to the squaric acid core were synthesized, and exhibited excellent photovoltaic performance.

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Recent advances in high-performance organic solar cells enabled by acceptor–donor–acceptor–donor–acceptor (A–DA′D–A) type acceptors

Materials Chemistry Frontiers ◽

10.1039/d0qm00305k ◽

2020 ◽

Vol 4 (12) ◽

pp. 3487-3504 ◽

Cited By ~ 1

Author(s):

Jiajun Zhao ◽

Chao Yao ◽

Muhammad Umair Ali ◽

Jingsheng Miao ◽

Hong Meng

Keyword(s):

Molecular Structure ◽

Solar Cells ◽

Organic Solar Cells ◽

High Performance ◽

Photovoltaic Performance ◽

Optoelectronic Properties ◽

Recent Advances ◽

Donor Acceptor

In this review, we focus on the recent advances in organic solar cells enabled by A–DA′D–A type acceptors and summarize the correlation between molecular structure, molecular packings, optoelectronic properties, and photovoltaic performance.

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Increasing donor-acceptor spacing for reduced voltage loss in organic solar cells

Nature Communications ◽

10.1038/s41467-021-26995-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Jing Wang ◽

Xudong Jiang ◽

Hongbo Wu ◽

Guitao Feng ◽

Hanyu Wu ◽

...

Keyword(s):

Solar Cells ◽

Organic Solar Cells ◽

Radiative Decay ◽

High Efficiency ◽

Bulk Heterojunction ◽

Perovskite Solar Cells ◽

Research Direction ◽

Voltage Loss ◽

Donor Acceptor ◽

New Research

AbstractThe high voltage losses ($${V}_{{loss}}$$ V l o s s ), originating from inevitable electron-phonon coupling in organic materials, limit the power conversion efficiency of organic solar cells to lower values than that of inorganic or perovskite solar cells. In this work, we demonstrate that this $${V}_{{loss}}$$ V l o s s can in fact be suppressed by controlling the spacing between the donor (D) and the acceptor (A) materials (DA spacing). We show that in typical organic solar cells, the DA spacing is generally too small, being the origin of the too-fast non-radiative decay of charge carriers ($${k}_{{nr}}$$ k n r ), and it can be increased by engineering the non-conjugated groups, i.e., alkyl chain spacers in single component DA systems and side chains in high-efficiency bulk-heterojunction systems. Increasing DA spacing allows us to realize significantly reduced $${k}_{{nr}}$$ k n r and improved device voltage. This points out a new research direction for breaking the performance bottleneck of organic solar cells.

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Towards high-efficiency non-fullerene organic solar cells: Matching small molecule/polymer donor/acceptor

Organic Electronics ◽

10.1016/j.orgel.2014.06.025 ◽

2014 ◽

Vol 15 (10) ◽

pp. 2270-2276 ◽

Cited By ~ 42

Author(s):

Pei Cheng ◽

Xingang Zhao ◽

Weiyi Zhou ◽

Jianhui Hou ◽

Yongfang Li ◽

...

Keyword(s):

Solar Cells ◽

Small Molecule ◽

Organic Solar Cells ◽

High Efficiency ◽

Donor Acceptor

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Constructing a donor–acceptor linear-conjugation structure for heterologous perylene diimides to greatly improve the photovoltaic performance

Journal of Materials Chemistry C ◽

10.1039/c8tc04929g ◽

2019 ◽

Vol 7 (4) ◽

pp. 835-842 ◽

Cited By ~ 12

Author(s):

Helin Wang ◽

Lingcheng Chen ◽

Yi Xiao

Keyword(s):

Solar Cells ◽

Electron Acceptor ◽

Organic Solar Cells ◽

High Efficiency ◽

Photovoltaic Performance ◽

Linear Conjugation ◽

Perylene Diimides ◽

Donor Acceptor

Th-4PDI, a new donor–acceptor-type non-fullerene electron acceptor material, was designed and synthesized for high efficiency organic solar cells.

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Branched Electron-Donor Core Effect in D-π-A Star-Shaped Small Molecules on Their Properties and Performance in Single-Component and Bulk-Heterojunction Organic Solar Cells

Energies ◽

10.3390/en14123596 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3596

Author(s):

Alexander N. Solodukhin ◽

Yuriy N. Luponosov ◽

Artur L. Mannanov ◽

Petr S. Savchenko ◽

Artem V. Bakirov ◽

...

Keyword(s):

Solar Cells ◽

Organic Solar Cells ◽

Bulk Heterojunction ◽

Photovoltaic Performance ◽

Charge Carrier Mobility ◽

Single Component ◽

Orbital Energy ◽

Donor Acceptor ◽

And Performance ◽

Acceptor Molecules

Star-shaped donor-acceptor molecules are full of promise for organic photovoltaics and electronics. However, the effect of the branching core on physicochemical properties, charge transport and photovoltaic performance of such donor-acceptor materials in single-component (SC) and bulk heterojunction (BHJ) organic solar cells has not been thoroughly addressed. This work shows the comprehensive investigation of six star-shaped donor-acceptor molecules with terminal hexyldicyanovinyl blocks linked through 2,2′-bithiophene π-conjugated bridge to different electron-donating cores such as the pristine and fused triphenylamine, tris(2-methoxyphenyl)amine, carbazole- and benzotriindole-based units. Variation of the branching core strongly impacts on such important properties as the solubility, highest occupied molecular orbital energy, optical absorption, phase behavior, molecular packing and also on the charge-carrier mobility. The performance of SC or BHJ organic solar cells are comprehensively studied and compared. The results obtained provide insight on how to predict and fine-tune photovoltaic performance as well as properties of donor-acceptor star-shaped molecules for organic solar cells.

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Sequential Deposition Enables High-Performance Nonfullerene Organic Solar Cells

Materials Chemistry Frontiers ◽

10.1039/d1qm00407g ◽

2021 ◽

Author(s):

Miaomiao Li ◽

Qi Wang ◽

Junwei Liu ◽

Yanhou Geng ◽

Long Ye

Keyword(s):

Solar Cells ◽

Organic Solar Cells ◽

High Performance ◽

Bulk Heterojunction ◽

Sequential Deposition ◽

Active Layers

Bulk-heterojunction active layers prepared by blend casting (BC) method have been predominantly used for more than two decades in the construction of organic solar cells (OSCs) with high efficiencies. Sequential...

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Nonfullerene Small-Molecule Acceptors with Extended Optical Absorption Based on the “Spliced” Strategy for Organic Solar Cells

Organic Materials ◽

10.1055/s-0039-3402049 ◽

2019 ◽

Vol 01 (01) ◽

pp. 071-077

Author(s):

Di Zhou ◽

Zhilin Liu ◽

Dangqiang Zhu ◽

Xiyue Yuan ◽

Xichang Bao ◽

...

Keyword(s):

Solar Cells ◽

Optical Absorption ◽

Band Gap ◽

Small Molecule ◽

Organic Solar Cells ◽

High Performance ◽

Photovoltaic Performance ◽

Wide Band ◽

End Capping ◽

New Perspective

How to broaden the optical absorption of photovoltaic materials is one of the key issues in the design of high-performance organic solar cells. Nowadays, the sunlight of 400–550 nm wavelength range is not effectively utilized for most small-molecule nonfullerene acceptors. In this work, we proposed the “spliced” strategy of combining the acceptor–donor–acceptor type narrow band-gap small molecules and wide-band-gap perylene diimide (PDI) moieties via a flexible alkyl chain linkage, which could give the superposition effect of the absorption spectra, and three small-molecule acceptors (S1, S2, and S3) were designed based on various end-capping groups with different electron withdrawing abilities. Encouragingly, the as-constructed molecules can well make use of 400–550 nm sunlight with two independent absorption regions. Meanwhile, the aggregation of S1 with a highly planar end-capping group was dominated by both the PDI unit and main skeleton, while S2 and S3 exhibited PDI-controlled aggregation. When fabricated into organic solar cells, S1-based devices achieved a superior efficiency of 3.41% in comparison with those of the other two. The poor photovoltaic performance could be attributed to severe PDI aggregation, which can hinder the charge transfer through the main skeletons. This work could provide a new perspective to modulate optical absorption through the spliced strategy.

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